1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly to a fabrication method for a semiconductor device capable of adjusting a thickness of each portion of gate insulating film at both sides of a gate.
2. Description of the Background Art
FIG. 1 is a vertical cross-sectional diagram of a conventional semiconductor device.
As shown therein, a predetermined portion of a gate insulating film 13b corresponding to a cell region 11b of a semiconductor substrate 11 is thickly formed by a gate re-oxidation process, and a mask 17 is formed on a portion of the gate insulating film 13a which corresponds to a periphery region 11a of the substrate 11 in order to prevent re-oxidation of a gate. The unexplained numerals, 15a and 15b, respectively indicate a gate, and 19 indicates a source/drain region.
Generally, according to the conventional semiconductor device, the gate re-oxidation process prevents damage of the gate insulating film occurred by etching or hot carrier stress of the gate and reduces gate induced drain leakage (GIDL). However, the gate re-oxidation process also reduces electrical properties such as a drain current and a threshold voltage, etc., thus a mask is formed on a predetermined area of the semiconductor device in order to prevent the re-oxidation of the gate.
However, because the gate re-oxidation process is essential to improve reliability of the gate insulating film, there is required a novel gate re-oxidation process that minimizes decrease of the drain current and threshold voltage, and further improves reliability of the semiconductor device.